Method of extracting or eliminating sulfur, phosphorus, and other impurities from coal, ore, &amp;c.



S SHEETS-SEEK?! 1.

Patented Aug. 23, 1910.

r L. L. SUMMERS. METHOD OF EX'IBAGTING 0B ELIMINATING SULFUR, PHOSPHOBUS, AND o'mnzu IMPURITIES PROM GOAL, ORE, a. urmouxon rnzn us. a, 1909.

W W JMeJAfi-M' Paimited Aug. 23, 1910.

Y L. L. SUMMERS. METHOD OF EXTBAO'IING 0E ELIMINA'IIRG SULFUR, PHOSPHOBUS, AND OTHER IMPUBITIBS FRO)! GOAL, ORE, &n. APPLICATION FILED APR 8, 1909.

UNITED STATES PATENT oFFroE;

LELAND L. SUMMERS, OF CHICAGO, ILLINOIS.

METHOD OF EXTRACTING on. ELIMINATING SULFUR, PHOSPHORUS, AND OTHER IMPURIILIES FROM COAL, ORE, &c. v

ed certain new and useful Methods of Extracting or Ellll'lilltl-Jllg Sulfur, Phosphorus,

and other Impurities from Coal, Ore, &c.,

of which the following is a specification.

My invention relates to a method of ex tracting or eliminating those impurities from coal ore, etc., which are both detrimental and troublesome in the manufacture of iron and steel, and the object is to provide a simple and efficient method of removing such impurities from the raw material used. Thus, according to my method, in the case of coal to be coked the sulfur, and phosphorus are removed from the coal before the same is charged into the. coking appliances, and in the case of ore, the impurities are removed previous to chargin the ore into the blast furnaces or other re ning apparatus.

'In general terms, my invention consists in providing a method by which the sulfur and phosphorus is chemically acted upon and its form of occurrence changed so that it may be removed as a different chemical compound. Sulfur and phosphorus in coal are very detrimental to its use as a fuel for metallurgical purposes. The sulfur in the coal exists in a number of different forms, part of the sulfur being combined in the coal in such manner as to pass 0!]? in a volatile form when the coal is coked or strongly heated. Another portion of the sulfur is combined with foreign matters in the coal, so that it may be eradicated previous to coking the coal. That portion of the sulfur combined in the coal and which forms a volatile constituent upon heating, does not exert a deleterious effect, as it does not remain inthe coke. However. the portion of the sulfur combined with iron and other matters is very difficult to remove, as upon heating the coal in a coke oven or furnace with a limited supply of air or oxygen the reducing atmosphere necessarily existing effectually prevents. removal of the sulfur.

As the general characteristics of phosphorus resemble those of sulfur in forming phosnhids and phosphates as sulfur forms sulfids and sulfates, the treatment for removing the sulfur will ordinarily result .in

Specification of'Letters Patent. Patented Aug. 23, 1910. Applicationfiled' April 8, 1909. Serial No. 488,721. i

the removal of phosphorus. Hence, in this specification the details covering the one will in general apply to the other.

As sulfur exists in much greater quantities than phosphorus in coal, the following detailed explanation will be made in connection with the removal and treatment of sulfur, although the method is equally a pplicable to the removal and treatmem of the phosphorus. Moreover, while for za:n venience I' will describe my invention in t nnection with an apparatus suitable fo; the practice of such invention or method, ysz'i is to be understood that my invention is not limited, in respect to the method, to any character of apparatus but that my method may be practiced in other ways.v 'Furthermore, I contemplate using my invention wherever applicable.

In the'drawings, Figure 1 is a vertical sectional elevation of an apparatus suitable for the practice of my invention; Fig. 2 a plan view of such apparatus but on a smaller scale; Fig. 3 a vertical-sectional elevation of a modified form of apparatus; Fig. 4 a plan view thereof; and Fig. 5 a detail elevation of the apparatus showing discharging means thereof.

Referring to the drawings, an electrolytic tank A of any suitable shape and dimensions is provided with revolving electrodes B and C mounted on an arm D and driven in any desired manner as by the gears E and E and pulley E which, in turn are driven by any suitable source of power (not shown). The electrode D is connected to the positive wire from a suitable source of electrical energy through the contact ring F and brush G. and the electrode C is connected with the negative lead from the same source of electrical energy through said contact ring and brush.

The electrolytic tank of Figs. 1 and 2 has a single compartment ir which the electrodes of different polarity revol e but if desired a double compartment tank may be employed as shown in Figs. 3 and 4 with electrodes of the same polar ty revolving in the same compartment. In this form of appal i i l electrodes C in av separate compartment, the

eral manner asthosealready described, but

in this instance theelectrodes B in compartment A are of the same polarity while those" in the othercom artment A are of the opposite polarity The electrodes B being in one compartment and the products of electrolysis are'thus separated as is well known in the art.

My method is based essentially upon the well-known fact that upon the passage of an elcctric current in a suitable electrolyte, electrolytic decomposition will result. According to my methc. aspracticed, the coal or ore to be 6lQCilOl}L3d is preferably in a finely subdivided form and is submerged in the electrolyte, so that upon revolving the electrodes B and C a continual agitation of the substance in contact with the products of electrolysis results. The electrolyte used may be varied to suit the characier of the impurities existing in the are or coal, the general action being as follows: A portion of the sulfur exists ordinarily in the form of the iron pyrites or hisulfid of iron FeS, Another portion of, the sulfur exists as the monosulfid of llOIl FeS,Jand still another portion exists as the sesquisullid Fe sg.

. electric. current, the acid radicalan oxy en traveling to the SJOSIUVB pole or The monosulfid is readily decomposed by dilute mineral acids with the evolution of hydrogen sulfid and a salt of the metal, in accordance with the following equations:

In my method of extracting the sulfur I preferably use an acid or acid-forming electrolvte such as sulfuric acid in water or any soluble sulfate which will have a combined decomposing action on the sulfids of iron, the acids converting the monosulfid into hydrogen disulfid and a soluble sulfate, at the same time that oxy en and water are decomposing the bisul d.

As the electrolyte is decomposed bv tlfie t e ano e causes an active an effective action on the substances in the vicinity of the anode. Thus, the particles of FeS are oxidized in the electrolyte, the product being is acted on by the acid.

Thchydrogen sulfid formed by the above reactions is decomposed by the oxygen, in; V

accordance with the following equation:

H S+OH O+S.

The product of this action is thus water and free sulfur. The sulfur'thus existing is inert to the acid and is but slowly oxidized by the oxygen.

coal then. treated separately with a solvent for-sulfur such as benzol C ll, or ethylalcohol C H O or electrolytically or otherwise with a solvent such as sodium hydroxid soluble ferrous and ferric sulfate and hy- V drogen sulfid, while the monosulfid of iron I I In this form the elecv trolytic action could be discontinued and the NaOH. If treated with a solution of so- 'dium hydroxid the sulfur will be placed in solution in the'form of sulfids and thiosulfates of sodium. Thus,

If desired the acid electrolyte may be drained from the tank or cell and an electrolyte of sodium hydroxid then placed thereinand the electrolytic action con tinned, with the result that the sulfur will I thus be acted on by the sodium hydroxid, which will be in an active e ectrolytic form. The alkaline solution taking the place of he acid solution will further a t on the soluble sulfates forming the iron hydrates. If an acid salt, precipitated by hydrogen sulfid be used, such as copper sulfate or a lead salt, it will be possible to have the sulfur deposited by the action of the hydrogen sulfid in the presence of these metallic salts decompose the metallic salt and form a metallic sulfid which may be caused to have a sufficient specific gravity so that the agitation from the revolving electrodes will cause these sulfids to sink to the bottom of the cell and be readily separated from the balance of the material treated. If the electrolyte used is such that'the presence of hy-v drogen sulfid may be caused to form a solsulfate is used, the deposited sulfur may be eliminated as a'soluble sulfid. The quality of the coal and the form in which the sulfur is obtained will ordinarily determine definitely which electrolyte to use.

In the above reaction, the electrodes B and C are assumed to be of carbon, platinum or other material not affected by the electrolytic action. If, however, a metal electrode such as copper is used in an acid electro- -uble sulfid such as will be the case when zinc lyte such as H 530 the metal will be disj solvedin the electrolyte and can be caused to unite with a portion of the sulfur as either soluble or non-soluble sulfates and sulfids depending on the metal used and the intensity of the reaction.

In ordinary practice with'the Illinois coals i i l l I prefer to use as an electrolyte a neutral xthe sodium. decomposes the water ,of the electrolyte, the products being hydrogen. and sodium hydroxid. The action willthus be to cause an acid reaction in the vicinity of the anode and an alkaline'rcaction in the vicinity of the cathode. By the reversal of the current or the reversal of the electrodes by revolving or otherwise agitating either the solution or the electrodes, this action may be reversed at will, that is, one portion of the electrolyte will be subjected to an acid and oxidizing influence, the other portion of the electrolyte being submitted to an alkaline and a reducing action from the libthe material treated to first be subjected to tioned.

the acid and oxidizingreaction and imn1ediately afterward to be subjected to the al kalinc and reducing action. Thus, the bisultid and monosulfid of iron in the vicinity of the anode will be violently reacted upon, the bisultid being oxidized and the monosulfid being decomposed as before men- Immediately after this action, the same particles will be subjected to the action of the sodium hydroxid liberated by the cathode, this'being caused by the rotation of the electrodes so that the cathode and anode are changing places. The rate of rotation is determined by the strength of the reaction desired.

In the apparatus of Fig. 3 the anode and the cathode occupy separate compartments, the passageof the current causing the acid and oxidizing rcaction to take place in the compartment A connected to the positive pole and an alkaline and reducing react-ion taking place in the compartment A connected to the negative pole. The agitation of the electrolyte in the revolving of both electrodes causes each particle to be subjected for a considerable time to the desired reaction. The current is then reversed. causing the compartment in which the acid and oxidizing reaction has been taking lace to be connected to the negative poe and the compartment in which the alkaline and reducing action has been to change from an aci taking place to be connected to the-positive pole, the effect being to reverse the reactions and the compounds formed in the two compartments will therefore be reversed. In this way the sulfur formed in the decomposition of the hydrogen sulfid and the pyrites is absorbed by-the alkali formed at the,

cathode. At each reversal of the current in the case of Fig. 3 or at each rotation of the electrode in the case of Fig. 1 a definite reaction is caused to take lace. The tendency d to an alkaline condition or vice-verse. immediately acts upon the compounds of sulfur which have been formed in the previous condition of reaction, the general tendency being to oxidize the sulfur into a soluble sulfate. In this way the chemical activity is constantly preserved and at the same time the violence of the re action can be easily controlled, so that a substance easily acted upon such as coal will not sutfer decomposition by the use of violently acting reagents. Thus, the use of a normal salt in the treatment of many coals possesses a distinct advantage, as the coking action of a coal is greatly afiectcd by both oxidizing or reducing actions if they are too strongly applied.

In decomposing a salt such as sodium sulfate into an alkaline and an acid radical, as above described, the sodium sulfate will be regenerated from the soluble sulfates when i the alkaline reaction forms the irem hydrates In treating iron ores this reaction will precipitate the sulfates acted upon in the form of pure ore as the hydrates decompose into the oxids, or inost common form of iron ore, and sodium sulfate is thus restored to the solution.

It will be apparent from the above description that I do not confine myself to the use of any one electrolyte, as the currentdensities used will permit the use of many acids or salts of acids and alkalis. In the treatment of many substances for the elimination of sulfur, it is undesirable to use a compound of sulfur and, hence, the acid reaction may be obtained by hydrochloric, nitric or other acids and the alkaline action or the solvent action obtained by other alkalies such as ammonia or by solvems for sulfur. Thus, the sodium nitrate or ammonium nitrate can be electrolyzed and an acid reaction due to the acid radical obtained, and the alkaline reaction simultancously obtained from the alkali liberated at the cathode.

The time required and the current densiparticular coal or ore treated. In general purities to he removed.

a current density of from two to three amperes per square inch of electrode'will pro duce satisfactory results in from three to.

five hours, depending on the amount of. im-

In the side elevation, Figs. 1 and 5, the

bottom J of the electrolyt1c cell is shown provided with a lateral extension or projection L. the action being that when the bottom of the cell is swung downwardly on its hinge and thereby dropped for discharging the material, the material in the cell A is discharged along the bottom, which forms a chute or sluice; The projection L, however, acting as a ritile, withholds that portion of the material wh ch was deposited at the bottom of the cell, and causes the por-- tion of the material in the upper parts of the cell to be freely discharged over the top agitation in the aqueous electrolyte will cause the heavier particles of slate, silica,

and mineral impurities to sink to the hottom of the cell. By means of the ritile L, the material in the lower. portion of the cell is readily separated without further action. In this manner the electrodes B and C may be used to cause a chemical reaction and precipitate portions of the sulfur or other impurities in a chemically combined form that will sink to the bottom of the cell while other portions of the impurities are being taken up in the manner above described, and in this way a combination of the methods may be utilized in one cell.

For convcment and rapid operation in supplying the tank with the electrolyte and draining the same therefrom and the substitution of other electrolyte as hereinhefore referred to, suitable mechanical means may be provided, as for instance the pump arrangement more or less diagrammatically shown in Fig. 1 where a centrifugal pump M is shown connected to the bottom of the tank with a discharge pipe m and provided also with a suction pipe 'm. which extends into a source of electrolyte within a suitable container such as the tank N. In order that the electrolyte may be drained back into the same tank or into some other tank if two characters of-electrolyte are used, I provide the discharge pipe m with a branch pipe M and provide such pipe with suitable shutoff valves m m all as clearly indicated in Fig. 1, suitable provision being of course provided to permit of the swinging bottom J of the tank in the manner already explained. v 7

Having thus described my invention, I claim:

1. The method of eliminating hosphorus or sulfur from coal ore, or the like, which consists in subjecting the material containing such substance or substances to electrolytic action by which an oxidizing and acid reaction is simultaneously produced.

The method of eliminating sulfur and phosphorus from coal ore or the like which consists in subjectingthe material containing such substance or substances to an elect-rolytic treatment by which the material is subjected to a combined acidifying and oxidizing reaction and then removing the secondary products by the action of suitable solvents.

. 3. The method of eliminating sulfur or phosphorus from coal ore, or the'like, which consists in alternately subjecting the material to an acidifying and oxidizing infinence and a reducing, and alkaline influence.

4. The method of eliminating sulfur or phosphorus from coal,'ore or the like, which consists in subjecting the material containing such substance or substances to electrolytic action, the electrolyte containing a solvcut for the products resulting from such action. V V

5. The method of eliminating sulfur or phosphorus from coal, ore or the like, which consists in subjecting the material containing such substance or substances to an aciditying and oxidizing reaction in an electrolyte in which the products resulting from the reaction are soluble.

- 6. The method of eliminating sulfur or phosphorus from coal, ore or the like which consists in subjecting the material to an d. The method of eliminating. sulfur or phosphorus from coal, ere or the like which consists in treatin the sulfur or phosphorus to be removed alternately with soluiions capable of forming compounds of sulfur or phosphorus and of oxidizing the sulfur or phosphorus into soluble compounds.

9. The method of eliminating sulfur from coal and the like, which consists in submerging the substance to be acted upon in a. suitable electrolyte, and then alternately subjecting the substance to the action of electrodes of opposite polarity.

10. The method of eliminating sulfur from coal and the like, which consists in as j submergin the substance to be acted upon in a suitable electrolyte and then alternately subjecting the substance to the action of sists in electrically treating the coal and then further treating the said'coal by suit- 10 able chemical re-agents to remove the sulfur. v

- 7 LELAND SUMMERS. Witnesses:

LOUISB. ERWIN,

ROBE T H. YDOBBERMAN. 

